Axolotl

Source: Wikipedia, the free encyclopedia.
For other uses, see Axolotl (disambiguation).

Axolotl
In the National Aquarium in Washington, D.C.

Critically Endangered  (IUCN 3.1)[1]
CITES Appendix II (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Ambystomatidae
Genus: Ambystoma
Species:
A. mexicanum
Binomial name
Ambystoma mexicanum
(Shaw and Nodder, 1798)
Map
IUCN range of the Axolotl.
  Axolotl (Ambystoma mexicanum)
Synonyms[3]
  • Gyrinus mexicanus Shaw and Nodder, 1798
  • Siren pisciformis Shaw, 1802
  • Siredon axolotl Wagler, 1830
  • Axolotes guttata Owen, 1844
  • Siredon Humboldtii Duméril, Bibron, and Duméril, 1854
  • Amblystoma weismanni Wiedersheim, 1879
  • Siredon edule Dugès, 1888

The axolotl (

Classical Nahuatl: āxōlōtl [aːˈʃoːloːtɬ] ⓘ) (Ambystoma mexicanum)[3] is a paedomorphic salamander closely related to the tiger salamander.[3][4][5] It is unusual among amphibians in that it reaches adulthood without undergoing metamorphosis. Instead of taking to the land, adults remain aquatic and gilled. The species was originally found in several lakes underlying what is now Mexico City, such as Lake Xochimilco and Lake Chalco.[1] These lakes were drained by Spanish settlers after the conquest of the Aztec Empire
, leading to the destruction of much of the axolotl's natural habitat.

As of 2020[update], the axolotl was near

Aztec diet.[11]

Axolotls should not be confused with the larval stage of the closely related tiger salamander (A. tigrinum), which are widespread in much of North America and occasionally become paedomorphic. Neither should they be confused with

mudpuppies (Necturus spp.), fully aquatic salamanders from a different family that are not closely related to the axolotl but bear a superficial resemblance.[12]

Description

A captive leucistic axolotl, perhaps the most well known form of the axolotl
Face of a common or wild type axolotl
The speckled wild type form
Axolotl's gills (Ambystoma mexicanum)

A sexually mature adult axolotl, at age 18–27 months, ranges in length from 15 to 45 cm (6 to 18 in), although a size close to 23 cm (9 in) is most common and greater than 30 cm (12 in) is rare. Axolotls possess features typical of salamander larvae, including external gills and a caudal fin extending from behind the head to the vent.[13][14] External gills are usually lost when salamander species mature into adulthood, although the axolotl maintains this feature.[15] This is due to their neoteny evolution, where axolotls are much more aquatic than other salamander species.[16]

Their heads are wide, and their eyes are lidless. Their limbs are underdeveloped and possess long, thin digits. Males are identified by their swollen

gill rakers
are hidden underneath the external gills, which prevent food from entering and allow particles to filter through.

Axolotls have barely visible

suction, during which their rakers interlock to close the gill slits. External gills are used for respiration, although buccal pumping (gulping air from the surface) may also be used to provide oxygen to their lungs.[15] Buccal pumping can occur in a two-stroke manner that pumps air from the mouth to the lungs, and with four-stroke that reverses this pathway with compression forces.

Buccal pumping
Axolotls displaying variations in color

Axolotls have four pigmentation genes; when mutated, they create different color variants. The normal wild-type animal is brown or tan with gold speckles and an olive undertone. The five most common mutant colors are listed below.

  1. Leucistic: pale pink with black eyes.
  2. Xanthic: grey, with black eyes.
  3. Albino: pale pink or white, with red eyes, which is more common in axolotls than other species.
  4. Melanoid: all black or dark blue with no gold speckling or olive tone.

In addition, there is wide individual variability in the size, frequency, and intensity of the gold speckling, and at least one variant develops a black and white piebald appearance upon reaching maturity. [17] Because pet breeders frequently cross the variant colors, double homozygous mutants are common in the pet trade, especially white/pink animals with pink eyes that are double homozygous mutants for both the albino and leucistic trait.[18] Axolotls also have some limited ability to alter their color to provide better camouflage by changing the relative size and thickness of their melanophores.[19]

Habitat and ecology

Lake Xochimilco, Mexico City (Amanecer en Xochimilco). The native habitat of axolotls is important to the study of preservation and conservation.
Wild form

The axolotl is native only to the freshwater of Lake Xochimilco and Lake Chalco in the Valley of Mexico. Lake Chalco no longer exists, having been drained as a flood control measure, and Lake Xochimilco remains a remnant of its former self, existing mainly as canals. The water temperature in Xochimilco rarely rises above 20 °C (68 °F), although it may fall to 6–7 °C (43–45 °F) in the winter, and perhaps lower.[20]

Surveys in 1998, 2003, and 2008 found 6,000, 1,000, and 100 axolotls per square kilometer in its Lake Xochimilco habitat, respectively.[21] A four-month-long search in 2013, however, turned up no surviving individuals in the wild. Just a month later, two wild ones were spotted in a network of canals leading from Xochimilco.[22]

The wild population has been put under heavy pressure by the growth of Mexico City. The axolotl is currently on the International Union for Conservation of Nature's annual Red List of threatened species. Non-native fish, such as African tilapia and Asian carp, have also recently been introduced to the waters. These new fish have been eating the axolotls' young, as well as their primary source of food.[23]

Axolotls are members of the tiger salamander, or

Ambystoma tigrinum, species complex, along with all other Mexican species of Ambystoma. Their habitat is like that of most neotenic species—a high-altitude body of water surrounded by a risky terrestrial environment. These conditions are thought to favor neoteny. However, a terrestrial population of Mexican tiger salamanders occupies and breeds in the axolotl's habitat.[citation needed
]

Diet

The axolotl is carnivorous, consuming small prey such as mollusks,[24] worms, insects, other arthropods,[24] and small fish in the wild. Axolotls locate food by smell, and will "snap" at any potential meal, sucking the food into their stomachs with vacuum force.[25]

Use as a model organism

See also: Model organism
Leucistic axolotl in captivity

Today, the axolotl is still used in research as a

heart defect studies due to the presence of a mutant gene that causes heart failure in embryos. Since the embryos survive almost to hatching with no heart function, the defect is very observable. The axolotl is also considered an ideal animal model for the study of neural tube closure due to the similarities between human and axolotl neural plate and tube formation; the axolotl's neural tube, unlike the frog's, is not hidden under a layer of superficial epithelium.[26] There are also mutations affecting other organ systems some of which are not well characterized and others that are.[27] The genetics of the color variants of the axolotl have also been widely studied.[18]

Regeneration

The feature of the axolotl that attracts most attention is its healing ability: the axolotl does not heal by scarring and is capable of the regeneration of entire lost appendages in a period of months, and, in certain cases, more vital structures, such as tail, limb, central nervous system, and tissues of the eye and heart.[28] They can even restore less vital parts of their brains. They can also readily accept transplants from other individuals, including eyes and parts of the brain—restoring these alien organs to full functionality. In some cases, axolotls have been known to repair a damaged limb, as well as regenerating an additional one, ending up with an extra appendage that makes them attractive to pet owners as a novelty. In metamorphosed individuals, however, the ability to regenerate is greatly diminished. The axolotl is therefore used as a model for the development of limbs in vertebrates.[29] There are three basic requirements for regeneration of the limb: the wound epithelium, nerve signaling, and the presence of cells from the different limb axes.[30] A wound epidermis is quickly formed by the cells to cover up the site of the wound. In the following days, the cells of the wound epidermis divide and grow quickly forming a blastema, which means the wound is ready to heal and undergo patterning to form the new limb.

It is believed that during limb generation, axolotls have a different system to regulate their internal macrophage level and suppress inflammation, as scarring prevents proper healing and regeneration.[31] However, this belief has been questioned by other studies.[32] The axolotl's regenerative properties leave the species as the perfect model to study the process of stem cells and its own neoteny feature. Current research can record specific examples of these regenerative properties through tracking cell fates and behaviors, lineage tracing skin triploid cell grafts, pigmentation imaging, electroporation, tissue clearing and lineage tracing from dye labeling. The newer technologies of germline modification and transgenesis are better suited for live imaging the regenerative processes that occur for axolotls.[33]

Genome

The 32 billion

genetic pathways that may be responsible for limb regeneration.[34] Although the axolotl genome is about 10 times as large as the human genome, it encodes a similar number of proteins, namely 23,251[34] (the human genome encodes about 20,000 proteins). The size difference is mostly explained by a large fraction of repetitive sequences, but such repeated elements also contribute to increased median intron sizes (22,759 bp) which are 13, 16 and 25 times that observed in human (1,750 bp), mouse (1,469 bp) and Tibetan frog (906 bp), respectively.[34]

Neoteny

Main article: Neoteny

Most amphibians begin their lives as

thyroxine in order for the axolotl to go through metamorphosis; therefore, it keeps its gills and lives in water all its life, even after it becomes an adult and is able to reproduce. Neoteny is the term for reaching sexual maturity without undergoing metamorphosis.[35]

The genes responsible for neoteny in laboratory animals may have been identified; however, they are not linked in wild populations, suggesting

artificial selection is the cause of complete neoteny in laboratory and pet axolotls.[36] The genes responsible have been narrowed down to a small chromosomal region called met1, which contains several candidate genes.[37]

Metamorphosis

The axolotl's body has the capacity to go through metamorphosis if given the necessary hormone, but axolotls do not produce it, and must be exposed to it from an external source, after which an axolotl undergoes an artificially-induced metamorphosis and begins living on land.

thyroxine or thyroid-stimulating hormone. The former is more commonly used.[37]

Role of iodine

In animals with functioning thyroid glands, iodine in the form of iodide is selectively gathered into the colloid of the thyroud. Inside the colloid, iodide is reduced to elemental iodine (I2), which reacts with the

tyrosyl residues of thyroglobulin. Two iodinated tyrosyl residues are conjugated together. When they are cleaved from the thyroglobulin chain, thyroid hormone is obtained.[39]

In the absence of induced metamorphosis, larval axolotls start absorbing iodide into their thyroid glands at 30 days postfertilization. Larval axolotls do produce thyroid hormone from iodide, but the amount appears highly variable. Adult axolotls do not produce thyroid hormone unless metamorphism is triggered.[40]

Lugol's solution, which contains both iodide and I2, triggers metamorphosis when injected.[42] This is because diiodotyrosine and thyroxine is produced when I2 reacts with proteins other than thyroglobulin. If given in a bath instead of injected, I2 has no effect on axolotls.[43] Iodide, which does not react with proteins, does not trigger metamorphosis. It does speed up the rate of metamorphosis, once it has been triggered by thyroid hormone extract.[44]

An axolotl undergoing metamorphosis experiences a number of physiological changes that help them adapt to life on land. These include increased muscle tone in limbs, the absorption of gills and fins into the body, the development of eyelids, and a reduction in the skin's permeability to water, allowing the axolotl to stay more easily hydrated when on land. The lungs of an axolotl, though present alongside gills after reaching non-metamorphosed adulthood, develop further during metamorphosis.[45]

An axolotl that has gone through metamorphosis resembles an adult plateau tiger salamander, though the axolotl differs in its longer toes.[citation needed] Among hobbyists, the process of artificially inducing metamorphosis can often result in death during or even following a successful attempt, and so casual hobbyists are generally discouraged from attempting to induce metamorphosis in pet axolotls.[45] Morphed pet axolotls should be given solid footholds in their enclosure to satisfy their need for land. They should not be given live animals as food.[46]

History

Six adult axolotls (including a leucistic specimen) were shipped from

Ambystoma velasci specimens were not included in the original shipment.[citation needed] Vilem Laufberger in Prague used thyroid hormone injections to induce an axolotl to grow into a terrestrial adult salamander. The experiment was repeated by Englishman Julian Huxley, who was unaware the experiment had already been done, using ground thyroids.[47] Since then, experiments have been done often with injections of iodine or various thyroid hormones used to induce metamorphosis.[16]

In other salamanders

Many other species within the axolotl's genus are also either entirely neotenic or have neotenic populations.

Sirens and Necturus
are other neotenic salamanders, although unlike axolotls, they cannot be induced to metamorphose by an injection of iodine or thyroxine hormone.

Neoteny has been observed in all

cretinism and dwarfism due to hypothyroidism
, as it does in humans.

Threats

Axolotls are only native to the Mexican Central Valley. Although the native axolotl population once extended through most of the lakes and wetlands that make up this region, the native habitat is now limited to Lake Xochimilco as a result of the expansion of Mexico City. Lake Xochimilco is not a large body of water, but rather a small series of artificial channels, small lakes, and temporary wetlands.

Lake Xochimilco is the only native habitat left for the axolotl.

Lake Xochimilco has poor water quality, caused by the region's aquaculture and agriculture demands. It is also maintained by inputs of only partially treated wastewater. Water quality tests reveal a low nitrogen-phosphorus ratio and a high concentration of chlorophyll a, which are indicative of an oxygen-poor environment that is not well-suited for axolotls.[49] In addition, the intensive use of pesticides from agriculture around Lake Xochimilco causes run off into the lake and a reduction of habitat quality for axolotls. The pesticides used contain chemical compounds that studies show to sharply increase mortality in axolotl embryos and larvae. Of the surviving embryo and larvae, there is also an increase of morphological, behavior, and activity abnormalities.[50]

Another factor that threatens the native axolotl population is the introduction of invasive species such as the Nile tilapia and common carp. These invasive fish species threaten axolotl populations by eating their eggs or young and by out-competing them for natural resources. The presence of these species has also been shown to change the behavior of axolotls, causing them to be less active to avoid predation. This reduction in activity greatly impacts the axolotls foraging and mating opportunities.[51]

With such a small native population, there is a large loss of genetic diversity. This lack of genetic diversity can be dangerous for the remaining population, causing an increase in inbreeding and a decrease in general fitness and adaptive potential. It ultimately raises the axolotl's risk for extinction, something that they are already in danger of. Studies have found indicators of a low interpopulation gene flow and higher rates of genetic drift. These are likely the result of multiple “bottleneck” incidents in which events that kill off several individuals of a population occur and sharply reduce the genetic diversity of the remaining population. The offspring produced after bottleneck events have a greater risk of showing decreased fitness and are often less capable of adaptation down the line. Multiple bottleneck events can have disastrous effects on a population. Studies have also found high rates of relatedness that are indicative of inbreeding. Inbreeding can be especially harmful as it can cause an increase in the presence of deleterious, or harmful, genes within a population.[52] The detection of introgressed tiger salamander (A. tigrinum) DNA in the laboratory axolotl population raises further concerns about the suitability of the captive population as an ark for potential reintroduction purposes.[53]

There has been little improvement in the conditions of the lake or the population of native axolotls. Many scientists are focusing their conservation efforts on translocation of captive-bred individuals into new habitats or reintroduction into Lake Xochimilco. The Laboratorio de Restauracion Ecologica (LRE) in the Universidad Nacional Autonoma de Mexico (UNAM) has built up a population of more than 100 captive-bred individuals. These axolotls are mostly used for research by the lab but plans of a semi-artificial wetland inside the university have been established and the goal is to establish a viable population of axolotls within it. Studies have shown that captive-bred axolotls that are raised in a semi-natural environment can catch prey, survive in the wild, and have moderate success in escaping predators. These captive-bred individuals can be introduced into unpolluted bodies of water or back into Lake Xochimilco to establish or re-establish a wild population.[54][55]

Captive care

See also: Herpetoculture
leucistic
, with less pigmentation than normal.
tapwater, is harmful to axolotls. A single axolotl typically requires a 150-litre (40-US-gallon) tank. Axolotls spend the majority of the time at the bottom of the tank.[58]

This animal was X-rayed several times as part of a research project over a period of two years. It was a normal healthy adult (26.3 cm; 159.5 gm) at the beginning of the project and lived several more years after the project ended.[59]

Salts, such as Holtfreter's solution, are often added to the water to prevent infection.[60]

In captivity, axolotls eat a variety of readily available foods, including trout and salmon pellets, frozen or live

bloodworms, earthworms, and waxworms. Axolotls can also eat feeder fish, but care should be taken as fish may contain parasites.[61]

Substrates are another important consideration for captive axolotls, as axolotls (like other amphibians and reptiles) tend to ingest bedding material together with food[62] and are commonly prone to gastrointestinal obstruction and foreign body ingestion.[63] Some common substrates used for animal enclosures can be harmful for amphibians and reptiles. Gravel (common in aquarium use) should not be used, and is recommended that any sand consists of smooth particles with a grain size of under 1mm.[62] One guide to axolotl care for laboratories notes that bowel obstructions are a common cause of death, and recommends that no items with a diameter below 3 cm (or approximately the size of the animal's head) should be available to the animal.[64]

There is some evidence that axolotls might seek out appropriately-sized gravel for use as

gastroliths[65] based on experiments conducted at the University of Manitoba axolotl colony,[66][67] but these studies are outdated and not conclusive. As there is no conclusive evidence pointing to gastrolith use, gravel should be avoided due to the high risk of impaction.[68]

Cultural significance

The species is named after the

Aztec deity Xolotl, the god of fire and lightning, who transformed himself into an axolotl to avoid being sacrificed by fellow gods. They continue to play an outsized cultural role in Mexico.[69] Axólotl also means water monster in the Nahuatl
language.

They appear in the works of Mexican muralist

International Bank Note Society.[72] HD 224693, a star in the equatorial constellation of Cetus, was named Axólotl in 2019.[73][74]

The

Pokémon Gold, Silver and Crystal (1999), is directly based on an axolotl.[69][additional citation(s) needed] The looks of the dragons Toothless and The Night Fury in the How to Train Your Dragon movies are based on axolotls.[69] They were also added to the video game Minecraft in 2020. It is following Mojang Studios' trend of adding endangered species to the game to raise awareness.[75] They were also added to its spin-off Minecraft: Dungeons in 2022 and are available in Lego Minecraft.[76] An anthropomorphic Axolotl named Axo was also added as a purchasable outfit in Fortnite Battle Royale on August 9, 2020.[77][78]

See also

References

  1. ^
    doi:10.2305/IUCN.UK.2020-3.RLTS.T1095A53947343.en
    . Retrieved 12 November 2021.
  2. ^ a b "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. ^ a b c Frost, Darrel R. (2018). "Ambystoma mexicanum (Shaw and Nodder, 1798)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 10 August 2018.
  4. ^ "Mexican Walking Fish, Axolotls Ambystoma mexicanum" (PDF). Archived from the original (PDF) on 15 March 2018.
  5. ^ "Axolotols (Walking Fish)". Aquarium Online. Archived from the original on 10 April 2013. Retrieved 2013-09-12.
  6. ^ Matt Walker (2009-08-26). "Axolotl verges on wild extinction". BBC. Retrieved 2010-06-28.
  7. ^ PetAquariums.com (22 April 2020). "Are Axolotls Endangered? You Need To Be Careful…". PetAquariums.com. Retrieved 2021-06-26.
  8. The Science Channel
    . 2009-11-11. Event occurs at 00:25.
  9. S2CID 260699417
    .
  10. PMID 36443330
    .
  11. ^ Tickell, Sofia Castello Y. (30 October 2012). "Mythic Salamander Faces Crucial Test: Survival in the Wild". The New York Times. Retrieved 30 July 2015.
  12. doi:10.1093/icb/18.2.195
    .
  13. Yda Addis
  14. ISBN 978-94-009-6536-2
    , retrieved 2021-05-13
  15. ^
    OCLC 1053847969
    .
  16. ^
    PMID 14576183
    .
  17. ^ "18 Types of Axolotl Colors You Can Own (Axolotl Color Guide)". August 14, 2019.
  18. ^
    doi:10.1111/j.1432-0436.1984.tb01393.x
    .
  19. S2CID 22723238
    .
  20. ^ "Lake Xochimilco, Borough of Xochimilco in southern México City, 162 L • Biotope Aquarium". Biotope Aquarium. Retrieved 2021-04-30.
  21. ^ Stevenson, M. (2014-01-28). "Mexico's 'water monster' may have disappeared". SFGate.com. Associated Press. Retrieved 2014-01-29.
  22. ^ "Endangered 'water monster' Axolotl found in Mexico City lake". The Independent. 2014-02-24. Retrieved 2017-06-02.
  23. ^ "Mexico City's 'water monster' nears extinction". November 2008. Archived from the original on 2011-07-23. Retrieved 2010-06-28.
  24. ^ a b "Ambystoma mexicanum (Salamandra ajolote)". Animal Diversity Web.
  25. PMID 2611639
    .
  26. PMID 3913733
    .
  27. doi:10.1002/dvg.1020060102
    .
  28. PMID 29291975
    .
  29. S2CID 31199048
    .
  30. PMID 31779024
    .
  31. PMID 23690624
    .
  32. S2CID 218792957
    .
  33. ^ Masselink, Wouter, and Elly M. Tanaka. "Toward Whole Tissue Imaging of Axolotl Regeneration." Developmental Dynamics, vol. 250, no. 6, 2020, pp. 800–806., https://doi.org/10.1002/dvdy.282.
  34. ^
    PMID 29364872
    .
  35. ^ Ley, Willy (February 1968). "Epitaph for a Lonely Olm". For Your Information. Galaxy Science Fiction. pp. 95–104.
  36. doi:10.1093/icb/18.2.195
    .
  37. ^
    PMID 31031711
    .
  38. PMID 30030457
    .
  39. ISBN 9781437717532.[page needed
    ]
  40. PMID 9371791
    .
  41. JSTOR 1536749
    .
  42. doi:10.3181/00379727-26-4212
    .
  43. PMID 20245954
    .
  44. doi:10.1007/BF00796048
    .
  45. ^ a b "Axolotls - Metamorphosed & Tiger Salamanders". www.axolotl.org. Retrieved 2022-01-25.
  46. ^ "Transition & Feeding". Morphed Axolotls.
  47. PMID 25920413
    .
  48. ^ Venturi, S. (2004). "Iodine and Evolution. DIMI-Marche". Archived from the original on 4 March 2017. Retrieved 25 September 2020.
  49. ISSN 1723-8633
    .
  50. PMID 19012946
    .
  51. S2CID 254550469
    .
  52. S2CID 46992721
    .
  53. PMID 28127056
    .
  54. S2CID 235587173
    .
  55. ISSN 0190-8286
    . Retrieved 2023-12-01.
  56. ^ "Axolotls – Requirements & Water Conditions in Captivity". axolotl.org. Retrieved 2016-03-14.
  57. ^ "Caudata Culture Species Entry – Ambystoma mexicanum – Axolotl". www.caudata.org. Archived from the original on 2016-03-15. Retrieved 2016-03-14.
  58. ^ Wiegert, Joshua. "Axolotls: Keeping a Water Monster".
  59. PMID 10461726
    .
  60. ^ Clare, John P. "Health and Diseases". axolotl.org.
  61. doi:10.1577/03632415.2011.10389070
    .
  62. ^ a b Pough, F. H. (1992). "Recommendations for the Care of Amphibians and Reptiles in Academic Institutions". Washington, D.C.: National Academy Press.
  63. PMID 17577564
    .
  64. S2CID 33299160
    .
  65. ^ Wings, O A review of gastrolith function with implications for fossil vertebrates and a revised classification Acta Palaeontologica Polonica 52 (1): 1–16
  66. ^ Gordon, N, Gastroliths – How I Learned to Stop Worrying and Love Gravel.
  67. ^ Björklund, N.K. (1993). Small is beautiful: economical axolotl colony maintenance with natural spawnings as if axolotls mattered. In: Handbook on Practical Methods. Ed.: G.M. Malacinski & S.T. Duhon. Bloomington, Department of Biology, Indiana University: 38–47.
  68. ^ Loh, Richmond (2015-05-15). "Common Disease Conditions in Axolotls". Vin.com. Archived from the original on 2020-08-04. Retrieved 2022-01-21.
  69. ^ a b c d "Mexico's axolotl, a cartoon hero and genetic marvel, fights for survival". Reuters. 2018-11-20. Retrieved 2022-08-16.
  70. ^ "Mexican axolotl will be the new image of the 50 peso bill". The Yucatan Times. 2020-02-21. Retrieved 2020-03-04.
  71. ^ "Billete de 50 pesos de la familia G". www.banxico.org.mx (in Spanish). Retrieved 2023-02-20.
  72. ^ "Banknote of 2021 Nominations". www.theibns.org. Retrieved 2023-02-20.
  73. ^ "Approved names". www.nameexoworlds.iau.org. Retrieved 2020-01-02.
  74. ^ "100 000s of People from 112 Countries Select Names for Exoplanet Systems In Celebration of IAU's 100th Anniversary". International Astronomical Union. December 17, 2019. Retrieved 2020-01-02.
  75. ^ Minecraft (October 3, 2020). ""Minecraft Live: Caves & Cliffs - First Look"". YouTube. "And then we also found out that axolotls are endangered in the real world, and we think it's good to add endangered animals to Minecraft to create awareness about that." - Agnes Larsson
  76. ^ "The Guardian Battle 21180". www.lego.com. Retrieved 2023-02-20.
  77. ^ "Fortnite v13.40 Leaked Skins: Axo, Castaway Jonesy, Crustina & More". 5 August 2020.
  78. ^ @FortniteGame (August 11, 2021). "Axo got a new style just in time for @maisie_williams & @reubenSelby's hand-picked Locker Bundle" (Tweet) – via Twitter.

External links

Wikimedia Commons has media related to Ambystoma mexicanum.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Axolotl&oldid=1220205699"